Fluorescent lamp illumination devices have traditionally been widely used in households, offices, and the like. Cold cathode fluorescent lamp illumination devices have also been used for liquid crystal display devices and television receivers. An ordinary fluorescent lamp such as a cold cathode fluorescent lamp is a light source in which an electrode is placed inside a glass tube where a prescribed gas has been sealed, and ultraviolet rays generated by electrical discharge are converted to visible light by hitting fluorescent material coated on the inner surface of this glass tube.
Meanwhile, the use of LED (light-emitting diode) illumination devices has been progressing in recent years due to the possibility of light illumination at a low voltage and high efficiency. Compared to fluorescent lamps and bulbs that use filament and the like, illumination devices using LEDs as a light source make it possible to reduce power consumption. A conventional illumination apparatus, which is one example of an illumination device that uses LEDs as a light source, is disclosed in Patent Document 1.
The illumination apparatus disclosed in Patent Document 1 has individual LED lenses that are elliptical in a cross-sectional view respectively provided on the light illumination side of a plurality of LEDs that are in a loop shape. The long axes of the respective LED lenses face the center of this loop shape. Accordingly, this conventional illumination apparatus widely emits light towards the center and the outside of this loop shape and has a uniform brightness.